babyfacefitz Posted June 14, 2016 Share Posted June 14, 2016 I've got an OBW 2001 H6 with the ac expansion valve "moan". When I first hook up my parts store $40 can/gauge the low side was way to high in pressure and the compressor was not engaging. I got the low side down in the working range and the compressor works and the moan comes and goes. When the system works in the heat of the day the moan is worse and the compressor fights so hard the RPM's are affected. I plan to change out my expansion valve and then recharge. I usually just use the $40 can/gauge and watch my low side gauge readings. ???? Should I do the right thing and by a $200 kit and vacuum out the system? I also don't like the idea of releasing all the R134a, doesn't that harm the environment? I vacuum kits that can store run around $300+. I like doing most of my own repairs so I wouldn't mind knowing if the "right way" is getting a vacuum kit. thanks Michael Quote Link to comment Share on other sites More sharing options...
babyfacefitz Posted June 14, 2016 Author Share Posted June 14, 2016 Oh I forgot to ask, what brand of expansion valve is recommended? Is the Four Seasons good? Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted June 14, 2016 Share Posted June 14, 2016 High pressure and a moaning expansion valve means there is air and moisture in the system. The valve is moaning because moisture is freezing on the outlet. Last I dealt with this was on a 95. The charge was low, and after re-filling the moan was reduced but not gone. Replaced the filter drier and vacuumed the system for about 2 hours to make sure there was no moisture in the system. Refilled and no more moan. If you don't want to release the refrigerant into the air (doesn't really hurt anything if you do) take it to a repair shop that has an AC recovery machine and have them evacuate the system before you replace your parts. Most likely you only need to replace the drier and have the system vacuumed. 1 Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 14, 2016 Share Posted June 14, 2016 I have bought a gauge set, and 'rented' a pump from a parts store - but, for the hassle/money, i think maybe having a good a/c tech take care of it might be just as good. If you are gonna maintain 2-3 older cars and like DIY, get a gauge set but rent a pump. If you are responsible for even more vehicles, maybe get a cheap pump from harbor freight? Quote Link to comment Share on other sites More sharing options...
babyfacefitz Posted June 14, 2016 Author Share Posted June 14, 2016 Thanks Fairtax4me, I'll get a vacuum kit, since I need it now and in the future. Where is the the filter drier? If I dry it out under a vacuum for an extended time, would the drier still need to be replaced? Quote Link to comment Share on other sites More sharing options...
babyfacefitz Posted June 14, 2016 Author Share Posted June 14, 2016 thanks lucky texan, I didn't know about renting a pump. I'll probably use the vacuum pump on my two OBW and other projects but renting might be the way to go. Quote Link to comment Share on other sites More sharing options...
987687 Posted June 14, 2016 Share Posted June 14, 2016 If I dry it out under a vacuum for an extended time, would the drier still need to be replaced? Yes, it's full of a desiccant and probably can't be completely dried unless it's heated. They're fairly cheap, if you're bothering to do the job properly, just replace it. 1 Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 14, 2016 Share Posted June 14, 2016 good info here; http://www.subaruoutback.org/forums/99-do-yourself-illustrated-guides/43428-diy-c-air-conditioning-leak-refrigerant-repair-5-less-15-minutes-less.html?highlight=diy+a%2Fc 1 Quote Link to comment Share on other sites More sharing options...
DaveT Posted June 14, 2016 Share Posted June 14, 2016 I have a compressor that I removed from a small old window a/c. I use it to recover refrigerant. It can also pull a pretty hard vacuum. When using it as a vacuum pump, you have to cycle the run time, otherwise it will overheat because the motor is cooled by the refrigerant - which is not there when pulling a vacuum. 1 Quote Link to comment Share on other sites More sharing options...
winginit Posted June 14, 2016 Share Posted June 14, 2016 I've got an OBW 2001 H6 with the ac expansion valve "moan". When I first hook up my parts store $40 can/gauge the low side was way to high in pressure and the compressor was not engaging. I got the low side down in the working range and the compressor works and the moan comes and goes. When the system works in the heat of the day the moan is worse and the compressor fights so hard the RPM's are affected. I plan to change out my expansion valve and then recharge. I usually just use the $40 can/gauge and watch my low side gauge readings. ???? Should I do the right thing and by a $200 kit and vacuum out the system? I also don't like the idea of releasing all the R134a, doesn't that harm the environment? I vacuum kits that can store run around $300+. I like doing most of my own repairs so I wouldn't mind knowing if the "right way" is getting a vacuum kit. thanks Michael i bought the cheap gauge and 12once can of coolant was about $40 at nappa, i change all the green O-Rings first also bought at nappa. i made sure the A/C system was empty. it was because it was empty. i Filled with one 12once can the gauge read about 35 i think , i have a arctic 43dagrees for a month now. PS make sure you buy the fill hose with the gauge they are a little more but u can see what is going on. Quote Link to comment Share on other sites More sharing options...
winginit Posted June 14, 2016 Share Posted June 14, 2016 the compressor will not start without coolant and pressure in the system. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 14, 2016 Share Posted June 14, 2016 depending on the model car - systems could 18-26 ozs, there should be a sticker under the hood or on the rail by the radiator with the capacity listed. Quote Link to comment Share on other sites More sharing options...
kamesama980 Posted June 14, 2016 Share Posted June 14, 2016 (edited) i bought the cheap gauge and 12once can of coolant was about $40 at nappa, i change all the green O-Rings first also bought at nappa. i made sure the A/C system was empty. it was because it was empty. i Filled with one 12once can the gauge read about 35 i think , i have a arctic 43dagrees for a month now. PS make sure you buy the fill hose with the gauge they are a little more but u can see what is going on. No, you just screwed your system. Just venting the system is not an empty system, it's a system full of air and humidity. Air (N2 and O2 mainly) in the AC system is a contaminant and detracts from the refrigerant capacity reducing efficiency. Moisture in the system reacts with the refrigerant and lubricant to create some nasty acids that eat the system from the inside out. i bought the cheap gauge and 12once can of coolant was about $40 at nappa, i change all the green O-Rings first also bought at nappa. i made sure the A/C system was empty. it was because it was empty. i Filled with one 12once can the gauge read about 35 i think , i have a arctic 43dagrees for a month now. PS make sure you buy the fill hose with the gauge they are a little more but u can see what is going on. If you want a worthwhile gauge, get a manifold gauge set, 3 hoses, 2 gauges. As for replace/recharge the filter dryer, while it might be possible to recharge the dessicant, it also acts as a filter for the system. it's uncommon but any metal shavings, dust, or other contaminants get caught in there. They're usually pretty cheap ($20-40) so it's cheap insurance. Obviously, con't uncap and install it until you're ready to vacuum down the system or you'll be letting it absorb moisture before you even start. If you want the system to last more than a season, you need to vacuum it down. Whether you buy or rent is up to you and how often you think you'll need it. Side note, not recovering and storing/recycling R134 is illegal. not that most automotive boards care about things like laws. Edited June 14, 2016 by kamesama980 Quote Link to comment Share on other sites More sharing options...
CNY_Dave Posted June 14, 2016 Share Posted June 14, 2016 (edited) I was a full supporter of bringing the car to a shop that could recover, and then later pull a vacuum for me. But- $75 disposal charge to recover, then another $75 disposal charge to pull a vacuum, on a system already vacuumed out? Bulllll-loney! Edited June 14, 2016 by CNY_Dave Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 14, 2016 Share Posted June 14, 2016 (edited) I was a full supporter of bringing the car to a shop that could recover, and then later pull a vacuum for me. But- $75 disposal charge to recover, then another $75 to pull a vacuum, on a system already vacuumed out? Bulllll-loney! I empathize with you, although I seem to be getting lazier as I age, I get so much help from the forum and I have no problem learning new skills or buying new tools, so, I DIY a lot. But, if there were 2 paychecks coming in and I had better things to do with my time, I might lean towards using a specialist/expert for some jobs. Plenty of people pay mechanics to fix their cars. Edited June 14, 2016 by 1 Lucky Texan Quote Link to comment Share on other sites More sharing options...
babyfacefitz Posted June 15, 2016 Author Share Posted June 15, 2016 (edited) is this what the drier looks like on my 2001 h6? thanks guys https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcSlO2MoI-suxfusd7RYknfAs6cBtyp94BI323V7S8ac_gTy4R-L4g Edited June 15, 2016 by babyfacefitz Quote Link to comment Share on other sites More sharing options...
babyfacefitz Posted June 15, 2016 Author Share Posted June 15, 2016 I found the drier container. Does the expansion valve need the rubber boot at the firewall. Mine is missing. Quote Link to comment Share on other sites More sharing options...
Theophilus Posted June 15, 2016 Share Posted June 15, 2016 I also don't like the idea of releasing all the R134a, doesn't that harm the environment? Yes, R134a is very definitely harmful to the environment. It doesn't attack the ozone layer, like the older refrigerants that contained chlorine, but it's still a powerful greenhouse gas that contributes to global warming. According to the New York Times (12/2/2007): "In wide use for little more than a decade, the shortcoming of R134a is revealed by a standard measurement called the Global Warming Potential, established to compare other gases with the most plentiful greenhouse gas, carbon dioxide. The warming potential of R134a refrigerant is 1,410, meaning that the release of one gram of R134a would have the same global warming effect as releasing 1,410 grams of carbon dioxide. The warming number of Freon-12, the common auto refrigerant used into the 1990s, is 8,500." So R134a isn't as bad as Freon-12, but it's still 1,410 times worse than carbon dioxide. That's why it's illegal to release it. Refrigerant recovery systems are too expensive for the home hobbyist, but you can take your car to anyplace that does AC repair work and they can take the R134a out of your system. If you get a high quote for the recovery work, shop around. They shouldn't charge you very much (if anything) because it only takes a few minutes and they get to keep the R134a that they recover. This video showing a Subaru AC system repair may be helpful: Quote Link to comment Share on other sites More sharing options...
CNY_Dave Posted June 15, 2016 Share Posted June 15, 2016 paying $75 twice to recover basically nothing (1st time) and testably absolutely nothing (2nd time) was my gripe. Quote Link to comment Share on other sites More sharing options...
DaveT Posted June 15, 2016 Share Posted June 15, 2016 Yes, if the system was already opened to fix what ever caused the lost refrigerant, there is nothing in it to recover. All you need to do at that point is to draw a vacuum to remove air and moisture, check for leaks, then charge. Quote Link to comment Share on other sites More sharing options...
winginit Posted June 15, 2016 Share Posted June 15, 2016 Yes, if the system was already opened to fix what ever caused the lost refrigerant, there is nothing in it to recover. All you need to do at that point is to draw a vacuum to remove air and moisture, check for leaks, then charge. Yes, if the system was already opened to fix what ever caused the lost refrigerant, there is nothing in it to recover. All you need to do at that point is to draw a vacuum to remove air and moisture, check for leaks, then charge. Yes, if the system was already opened to fix what ever caused the lost refrigerant, there is nothing in it to recover. All you need to do at that point is to draw a vacuum to remove air and moisture, check for leaks, then charge. yeah my system was empty already, my a/c cranks ill take my chances.. Thanks Quote Link to comment Share on other sites More sharing options...
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